1. Field of the Invention
The present invention relates to a communication system for transmission/reception via a transmission medium such as a human body.
2. Description of the Related Art
Accompanied with the recent technical development, the totally new communication method using the electric field guided to a transmission medium such as the human body has been proposed. A receiver of the aforementioned communication system as disclosed in Japanese Unexamined Patent Application Publication No. 2005-94466 includes a reception electrode for receiving a signal generated from a signal source, and a resonance circuit for extracting the signal at a prescribed frequency. The resonance circuit formed of an air-core coil and a chip capacitor has an end of the air-core coil connected to the reception electrode which faces the human body.
In the communication system disclosed in Japanese Unexamined Patent Application Publication No. 2005-94466, if the distance between the human body and the reception electrode of the receiver extends by a very small amount, the communication will be disabled or interfered owing to the noise close to the carrier frequency of the communication (for example, the noise generated by the mobile phone).